The damage felt by the Mossad over the release of footage of the hit on Mahmoud al-Mabhouh is now likely to be suffered by the Shin Bet security service with next week's publication of Mosab Hassan Yousef's memoir.

"The Green Prince" was apparently among the highest ranking agents the security service operated among Hamas' military wing in the West Bank, the most murderous terror network ever known in the Palestinian territories.

In his book, and in his interview with Avi Issacharoff (to be published in full Friday), Yousef exposes the methods by which the Shin Bet almost entirely obliterated the network by which hundreds of Israelis were murdered in terrorist attacks between 2000 and 2005.

Whether the Shin Bet learned of the book when Haaretz filed its article to the military censor earlier this week, or whether it knew of it earlier, Israel's internal security service had two options: try to prevent the book's publication or come to terms with it in the hopes of somehow using it to its advantage in the future.

Shin Bet chief Yuval Diskin certainly remembers the precedent of Victor Ostrovsky. When in 1990, Ostrovsky, a former Mossad case officer, was preparing to release his memoir in Canada, then-prime minister Yitzhak Shamir and Mossad chief Shabtai Shavit tried to use the court to keep it off bookshelves.

Their efforts had the opposite effect. Not only did the Canadian court refuse to intervene, but the clumsy Israeli reaction seemed to add credibility to the book's accounts, some of them clearly exaggerated, and catapulted Ostrovsky to the international bestseller list.

This time, Shin Bet decided not to comment on the matter. As far as is known, no significant pressure was applied on him to prevent the book's release, or even to prevent Yousef's former handlers from responding.

It's doubtful such efforts would ever have worked. Yousef is an extraordinary person who for years has lived on the edge, having violated his loyalty to his father, a Hamas leader in the West Bank, and the movement and nation in which he was raised. He unflinchingly put his life in danger to save Israeli lives, and both Yousef and his former handlers maintain money was not his primary motive.

Since fleeing the West Bank in 2007, he has burned every possible bridge, starting with his Haaretz interview the following year in which he denounced Hamas as a bloodthirsty band of terrorists and announced he had converted to Christianity. Now he has taken this betrayal a step further, revealing that for over a decade he worked for the Shin Bet.

To the Israeli reader - on the assumption that most of the book's contents are accurate - Yousef is an encouraging figure. As with other reports to emerge in recent years, his collaboration reflects the impressive intelligence coverage Israel has attained over its enemies.

It is common to speak of Israel's aptitude in signal intelligence, particularly the technological achievements of Unit 8200, the central collection unit of Military Intelligence.

But here is a human source who apparently operated for years in the heart of Hamas' operational apparatus, providing invaluable intelligence without being exposed.

Israel's success against Palestinian terrorism, obtained with tremendous effort, has restored the feeling of relative security to citizens' everyday lives.

The case of the "Green Prince" is now proving that this success may be attributed in no small part to Palestinian agents. It's safe to assume that unlike Yousef, the vast majority would prefer to remain anonymous.

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